As noted in the previous post at this blog, there appears to have been maritime trade network that extended from Southern Sweden to Cyprus in the Bronze Age (ca. 1500 BCE and later).
How long would it have taken to sail the entire distance and back?
Resort to an atlas (giving the benefit of the doubt to the ability of ancient sailors to take straight oversea routes rather than hugging the coast), shows that the total distance by sea is about 4000 nautical miles one way, and hence an 8000 nautical mile long round trip.
Based upon historically attested reports of travel times by sail in the Roman era, sailing speeds averaged about four knots with favorable winds and about two knots with unfavorable winds.
Canny pre-modern sailors probably knew the wind patterns well enough to time their trips so that they had favorable winds at least half of the time, suggesting an average speed of at least three knots over such a long, multistage journey.
This would suggest a one way travel time of about 56 days of travel time, and a round trip travel time of about 112 days.
But, while the trips used to calibrate these speeds in the Mediterranean may have been mostly direct trips, for a trip of this distance, probably at least two days a week and possibly more to conduct the trade that was the point of these cruises, would have been spent in port.
This gives us our answer (below the jump):
The round trip travel time for this epic Bronze Age journey would probably have been on the order of five or six months.
What kind of life for sailors does this imply?
One imagines a crew that might have spend half of the year each year for a number of years making this trip, and the other half of their year farming, herding, engaging in commerce and civic activities, building and repairing ships, spending time with spouses and children, and making war.
Certainly, it would be far less than the many years Odysseus and his crew endure over a considerably smaller distance in the Greek epic set in this historical era (but only recounted in writing many centuries later) never leaves the Mediterranean.
These would certainly be long trips, but given that they would be made up of many, much shorter port to port hops, with well established routes, and would involve long portions of the trip within sight of shore, it would have been less terrifying than the exploratory cross-oceanic trips taken by Columbus and other maritime explorers of the 15th and 16th centuries of the current era.
Did anyone make the round trip?
Of course, it is far from certain that the same crew would have made the entire journey most of the time. If one imagines sailors leaving and returning from a Southwestern Iberian hub, each crew's longest journey might have been only about three months or less (on average six or seven weeks each way), with the Greek sailors scarcely leaving the Mediterranean, and the Iberian and Swedish sailors on the Atlantic coastal route never entering it, with some crews possibly making more than one trip each year.
Also, if the system did have a hub and spoke organization, the Atlantic leg and the Mediterranean leg, respectively, of each trip would have involved a fairly small number of distinct cultures, reducing the cultural strain on the crews trying to adapt to customs in each new port and limiting the amount of linguistic expertise required for any one crew.
There is some circumstantial evidence that this was how the trade system was organized. One would think that if Greek sailors had personally made the entire trip on a fairly regular basis, that some trace of the epic journey would have at least survived in legends or myths, or perhaps more reliable historical accounts. But, I know of no classical Greek or Roman account (or Scandinavian account) of a Bronze Age sailor traveling the entire length of this trade route personally or even being aware of just where the other extreme of the route was located.